Resins obtained by curing known cyanic acid ester monomers are excellent in thermal and electrical properties, but they are limited in use because they are so poor in the mechanical properties of toughness and flexibility.
U.S. Pat. No. 3,595,900, issued July 27, 1971, discloses a process in which hydroxy-terminated polyarylene ethers are reacted with cyanogen halides to produce cyanatophenyl-terminated polyarylene ethers which can be thermally polymerized to produce polyarylene ether cyanurates.
U.S. Pat. No. 4,026,913, issued May 31, 1977, relates to cyanic acid esters prepared by reacting an aromatic polycarbonate having one or two terminal hydroxyl groups with a cyanogen halide in an inert solvent in the presence of a base.
U.S. Pat. No. 4,046,796, issued Sept. 6, 1977, discloses a process for the production of aromatic polyfunctinal cyanic esters by reacting the alkali or alkaline earth metal salts of aromatic di- or polyhydroxy compounds with halogen cyanides in a solvent, optionally in the presence of catalytic quantities of a tertiary amine.
U.S. Pat. No. 4,157,360, issued June 5, 1979, discloses a thermoformable composition consisting of a crosslinked cyanurate polymer and a thermoplastic polymer.
U.S. Pat. No. 4,403,073 discloses a curable resin composition comprising at least one cyanate compound, a polybutadiene compound and a polyfunctional maleimide compound.
It has now been found that a cured resin material comprising a dicyanate-terminated aromatic polysulfone and/or polyketone oligomer component, a cyanate ester component and a bismaleimide component has excellent mechanical properties, good thermal stability and low moisture absorption.